Replace final sprintf() with snprintf() in psa_ff_server.c

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/tests/psa-client-server/psasim/src/psa_ff_server.c b/tests/psa-client-server/psasim/src/psa_ff_server.c
index ea797d8..7c72ee7 100644
--- a/tests/psa-client-server/psasim/src/psa_ff_server.c
+++ b/tests/psa-client-server/psasim/src/psa_ff_server.c
@@ -638,7 +638,7 @@
         if (strncmp(array[i], "", 1) != 0) {
             INFO("Setting up %s", array[i]);
             memset(queue_path, 0, sizeof(queue_path));
-            sprintf(queue_path, "%s%s", TMP_FILE_BASE_PATH, array[i]);
+            snprintf(queue_path, sizeof(queue_path), "%s%s", TMP_FILE_BASE_PATH, array[i]);
 
             /* Create file if doesn't exist */
             fp = fopen(queue_path, "ab+");